JOHNPAUL

I've noticed kinda sorta a flat spot upon acceleration , somtimes.

I've read flatlines post a while back and I thought I read that the car should run on the secondary distributer ,

I disconected the secondary and the car started and ran fine , (idle only) . I reconected that one , disconected the primary dist/ tried to start the car ,it wanted to but would not run ???

I think I have a problem?

after I reconected the primary and the car ran fine.

Gary C2

Your distributor belt is broken.

JOHNPAUL

I just checked the belt by removing both caps and rotors , (couldn't sleep) . The belt looks new and tight , no dusting or spliting . inside the dist. housing is fairly clean just a few drops of oil down at the bottom of the secnd. dist. Both dist spin while cranking the car .

From reading past post I'm thinking I have a bad coil , can I just change the leads to the dist to check them ?

Gary C2

Yes, swapping the leads will either comfirm that the coil is bad or good. Also check the connector that it is fully seated and check the connector pins for corrosion.

Adrian

A common 964 igntion system failure is the high voltage lead from the coils to the distributors. Check around the area to see if there is any evidence or arcing. Often you cannot see that the lead has broken down. However coils overheat are also quite common and this causes the coil to breakdown. A high volage lead tester can normally sort out the problem. The 964 engine should continue to run on the secondary coil system but I am not not convinced that it will actually start off the secondary. Not something that is is tested often for obvious reasons,
Ciao,
Adrian
911C4

Roland Kunz

Hello

You can swap over the coils and Hybrids to check out if it will "move on".

How old are the sparkplugs and ign. wires ?
Firing order correct ?

Grüsse

Gary C2

The engine will start with just the secondary.

Gary

JOHNPAUL

I'm sorry guys , I didn't get a chance to play with the Porsche today .

I was busy trying to get my bmw put back together . If my wife comes home from out of town and see's both cars torn apart I'll be in big trouble .

I for sure have a problem , cause the car would not start on the secondary coil .

I wont drive the P-car till I clear this up .
Thank you very much ,

mikeP

Here is my experience with the dual distributor belt. I have a 91 C4, bought new, now with 55k miles. I had the distributor vent installed as soon as it was availbale, i think within the first year. A few days ago the car started to run very rough, with very low power. No question that something was seriously wrong. It felt as if the car was running on 4 or 5 cylinders. It turns out that the belt was broken and the second distributor rotor was stuck (I think due to gravity) pointing to one plug. A rebuilt distributor from Porsche (~$400) and all is well. A few years ago I experienced a defective (new) distributor cap. The effect of that was very different, slight hesitation at higher RPMs and a slight decerease in power. If the belt brakes (and the rotor points to a plug) you will know instanteneously that something is seriously wrong.

Fred, Long Island

400 for a rebuilt? I guess it's a good price considering the source but it is a shame that you didn't try to rebuild it yourself. It's not that daunting a task and the belt is less that 10 dollars.

Bill Gregory

[quote]<strong>400 for a rebuilt? </strong><hr></blockquote>

Although not as inexpensive as doing it yourself, you can get the Porsche reconditioned distributor from Reeves Porsche in Tampa for around $275.

Mueller

Picking up my new to me '91 C2 tonight after work....

It does NOT have the hose kit for the venting of the dizzy belt...I have already purchased a new belt, so where can I find directions for replacing the belt?

Thanks

Johnny G Pipe

Mueller

I too have been contemplating this task as my 80k mile C4 came with no vent tube. So far I haven't had the ***** (don't like the idea of taking a drill to my distributors!)....but one of the 'running reports' contributors from 911+PW, Nick White, did, and invited e-mails from others attempting it.
His reports are reproduced at <a href="http://www.porsche964.co.uk," target="_blank">www.porsche964.co.uk,</a> but they don't give any actual directions. He found instructions via Pelican parts, but apparently it took him all day to do the job....let us know how you get on!

Bill Gregory

Installing the vent kit to the distributor is a snap. From the Porsche Technical bulletin (number 9403, group 2, entitled "Ignition Distributor Ventilation"), you drill an 18mm hole approx 40 mm to the right of the tail light vent tube in the air guide tube which leads from the blower to the heat exchangers. You may want to remove the air guide tube before you drill into it. Drill, then deburr the hole and insert the rubber grommet (#2 below) into the hole, then the 90 degree plastic connector (#3 below). Reinstall the air guide tube if you removed it. Use a screwdriver and remove the oval plate on the righthand distributor (as looking at them from outside the engine compartment). The oval plate is lightly pressed into the distributor body - it's OK to tap the screwdriver into the plate to pry it out, as you'll be discarding the oval plate. Install the ventilation connector (#1 below) into the distributor, and connect the hose between the distributor and the air guide pipe. Done. Here's the diagram from the technical bulletin:



The Porsche part number for the ventilation kit is 000.043.202.52. Costs around $10.

JOHNPAUL

Just an update , I found the dist belt to be in great shape . After switching the coil wires around I found that one of the coil wires boot , where it plugs into the coil was arcing to the termanals on the coil itself .I replaced the coil wires and the "flat spot" is gone.....